Measuring and controlling apparatus for catalyst regenerators



Feb. 7, 1950 w. P. WILLS ,0

MEASURING AND CONTROLLING APPARATUS FOR CATALYST REGENERATORS Original Filed April 23, 1942 CATALIZED VAPOR Soumzr PIPE M INVENTOR.

WALTER P. WILLS AT TO EY.

said valves are adapted for operation in suitably timed relation by the adjustment of a single pole double throw switch 30 between positions in which it respectively engages spaced apart contacts 3i and 32. When the switch 30 is moved into engagement with the contact 3| it opens the valves i2 and I4 and closes the valves i6 and ll, and when moved out of engagement with the contact 3! it effects closures of the valves I 2' and i4 and the opening of the valves i6 and i1. When the switch 3!! is moved into engagement with the contact 32 it similarly opens the valves 22' and 24', and it closes thevalves 23 and 21' 1 and when moved out of engagement with the contact 32 it opens the two valves last mentioned and closes the valves 22' and'24'.

The same cyclic operations are effected in the chambers i3 and 23. The opening and closure of a solenoid valve IS in the hot air supply pipe i8 respectively permits and prevents hot air from passing through-whichever of the valves l6 and 25' may then be open. Similarly, the opening and closure of a solenoid valve IS in the steam supply pipe l9 permits or prevents the passageof steam from said pipe through whichever of the valves la and '26 is theniopen. In the regeneration of the chamber It, the hot air supply valve I8" is open and the steam supply valve I9 is closed during periods in which the temperature in thechamber I3 is suitably low, but on a sufficient increase in the temperature in the chamber I 3, a measurin and recording instrument 33, responsive, as hereinafter explained, to the temperature in the chamber 13 and to the rate at which that temperature changes, closes the valve I8 and opens the valve [9, so that the interruption of the hot air supply and. the initiation of the supply of steam to the chamber l3 will prevent objectionable overheating of the catalytic material in that chamher.

In the arrangement diagrammatically shown in Fig. 1. the valves I8 and i9 are biased to open and closed positions, respectively, and are moved into their closed and openpositions. respectively, only when their solenoid coils are energized. The solenoid coils of the two valves. are connected in parallel in an energizing circuit 34. which is closed by the instrument 33 in any suitable manner on a predetermined movement of the instrument pen carriage 35. For example, the instrument pen carriage 35 may include an arm 35', which closes a switch 36 in the circuit 3 shown in Fig. 4, on a'predetermined' extent of movement of the pen carriage 35 toward the high temperature end of its range of movement. As shown in Fig. 4, the switch 36 is a mercury switch pivoted on a support 35'. The support 36' may be adjusted longitudinally of the pen carriage path of movement to thereby vary'the pen carria e position at which the arm 35' engages the switch 36 and tilts it into its closed position. In the latter position, the switch 36 operatively connects the circuit 34 to suppl conductors 3! and 38 and therebyenergizes thesolenoid coils of the valves i8 and I9. The switch36 is biased for movement into itsv open position and opens as soon as the pen carriage 35 moves back toward the left, or low temperature, end of its range 'of movement. As shown in;Fig. l, a lamp. or other signal 39 is connected in parallel with the solenoid windings of the valves {8? and I55 in the energizing circuit 34 so that-thesignal device will indicate the temperature condition in thechamber undergoing regeneration which causes the 4 hot air supply valve 18' to close and the steam valve 59' to open.

As diagrammatically shown in Fig. 1, the means through which the instrument 33 is made responsive both to the magnitude and to the rate of change of the temperature in the chamber l3, comprises thermocouples 4i and 42 in said cham ber. Similar thermocouples 4| and 42 in the chamber 23 are used to make a control instrument responsive to the magnitude and rate of change of temperature in the chamber 23.

The instrument 33 may be connected to the thermocouples 4i and 52 in the chamber l3 during the regeneration of that chamber, and may be connected to thermocouples 4i and 42 in the chamber 23 during the regeneration of the latter or the last mentioned thermocouples may be connected to a separate but similar control instrument through which the energization of the valves i8 and iii are controlled by the temperature conditions in the chamber 23.

The steam supplied by the pipe l9 may be at a temperature of the same order as the temperature of the hot air supplied by the pipe i8. Even if the steam supplied is at the same temperature as the hot air, the interruption of the hot air supply and the initiation of the steam supply to the chamber, i3 or 23, undergoing regeneration, will prevent further increases in temperature in that chamber and ordinarily will effect a reduction in the temperature inthat chamber, since the reaction of the hot air with hot carbon is exothermic, while the reaction of the superheated steam with hot carbon is endo thermic. In the regeneration of catalytic material in apparatus'of the type diagrammatically shown in Fig. 1, the temperature of the catalytic material may increase in a very few minutes from a normal working temperature of 840 or so, to a maximum safe regeneration temperature in excess of 1100. Because of the rapid and substantial changes in catalyst temperature and the importance of limiting the rise in the catalyst temperature, control apparatus which takes into account not only the temperature, but also the rate of temperature change I in the" chamber undergoing regeneration is especially desirable.

The manner in which the thermocouples 4i and 4'3 in the chamber !3, shown in Figs. 1 and 2 are associated with one another and with the instrument will now be described. 'The in" strument 33 is a self balancing recording and controlling potentiometer instrument. The thermocouple 4! is connected in serieswith a resistance i3 and a mirror type galvanometer 44 in the measuring circuit of the instrument 33. The thermocouple 42 hasone terminal. directly connected to one terminal of the resistance 43.and has its second terminal connectedthrough a condenser 45 to the second terminal of the resistance 43. The measuring circuit of theinstrument 33 includes a slide wire 53, a contact 5| in engagement with and adjustable,longitudinally along the slide wire 5%, an energizing battery 52, and a resistance 53 adjustable to insure the desired potential drop in the slide wire. The thermocouple 4! has one terminal connected to one end of the slide wire 50, and has its other terminal connected through the resistance 43 and galva= nometer 44 to the movable contact 5|.

7 When the potential of the thermocouple 42 has been constant long enough for its potential and that of the condenser 45 to equalize, the condenser prevents the thermocouple ,42 from having any effect on the current flow through the galvanometer 44. However, on achange in the temperature to which the thermocouple 42 is subjected, the corresponding increase or decrease in its potential results in the flow of a condenser charging or condenser discharging current through the resistance 43, and the resultant change in the voltage drop in that resistance has the effect of temporarily adding to or subtracting from the voltage impressed by the thermocouple 4| on the circuit branch including the galvanometer 44.

The thermocouple 42, condenser 4'5, and the resistance 43 combine to form an element creating a potential difference which is a measure of the rate of change of the temperature of the thermocouple. Furthermore, the last mentioned element is combined with the thermocouple 4| to form a second element creating a potential difference Which is the algebraic sum of the E. M. F. created by the thermocouple 4|, and the potential difference created by the first mentioned element. The proportion of the potential difference jointly created by the thermocouples 4| and 42 which is contributed by the thermocouple 42 may be varied as desired by the adjustment of contact 43, provided in slideable engagement with the resistance 43 and which permits tapping off a desired part of the potential drop across resistance 43. The potential difference which the two thermocouples 4| and 42 jointly create, is of a character to be measured by potentiometric means operating on the null principle and of which the instrument 33 is one form.

The mirror galvanometer 44 reflects light from a light source 55 onto photoelectric cells 56 and 51, which, as shown are enclosed in a common envelope, and are connected to the input terminals of an electronic amplifier 58. The latter, shown in Fig. 2 and hereinafter described in detail, is energized from alternating current supply conductors 59 and 60, and has its output terminals connected to the terminals of a reversible motor 6|.

When the potentiometric measuring circuit is balanced and the galvanometer 44 occupies its neutral or intermediate deflective position, equal amounts of light are reflected onto the cells 56 and El, and the motor BI is not energized for rotation in either direction and remains stationary. However, when the measuring circuit is. unbalanced the galvanometer deflects out of its neutral position, and one of the cells 56 or 51 receives more light than the other. The motor 6i is then energized for rotation in a direction dependent on which cell receives the more light. The motor 3| is mechanically connected to and rotates the threaded pen carriage shaft '52 of the instrument 33 and thereby adjusts the pen carriage 3e longitudinally of said shaft. The pen carriage 35 carries the contact ii I which is moved by the carriage in the direction to rebalance the potentiometer circuit. The pen carriage also supports a recording pen 63 which traces: a record of the penv carriage movement on a record strip or chart 64. The latter is advanced by a constant speed motor 65. When the potentiometer is balanced, the length of the portion of the slide wire 50 at the left of the contact 5| in Fig. 2 is such that the potential dropin said portion, due to the current flow produced by the battery 52 is equal in magnitude and opposite in direction to the potential impressed on said slide wire by the circuit branch 6 including the thermocouple 4| and galvanometer 44.

On a subsequent increase or decrease in the furnace temperature, the potential impressed on the said slide wire portion by the said circuit branch is increased or decreased as a result of the increase or decrease in the voltage of the thermocouple 4|, and is further increased or decreased as a result of the change in the voltage of the thermocouple 42 and the resultant change in the potential drop in the resistance 43 due to the flow of the charging or discharging current of the condenser 45. When the potentiometer is thus unbalanced, the motor ti operates in the the flow of the charging discharging current of direction to move the contact SE to the right or to the left as required to rebalance the poten tiometer.

The increased or decreased voltage of the thermocouple 4i, due to the above mentioned change in furnace temperature, is maintained until a further change in the furnace temperaturs occurs. following its initial change, the furnace temperature remains constant for a period, the condenser charging or discharging current fiow created by an initial change in the voltage of the thermocouple 42 will correspondingly vary the potential of the condenser and die out. As the condenser current thus dies out, the portion of the potential drop in the resistance it created by the condenser current will also die out, and thus have the effect of producing a reverse potential rebaiancing operation of the motor iii, and a return movement of the contact 5| into the position in which it correctl indicates the existing temperature of the thermocouple 4|.

As will be apparent, the potential drop in the resistance 43 in one direction produced by a condenser charging current, or in the opposite direction produced by a condenser discharging current, is in each case proportional to the mag nitude of the current and, hence, in each case is directly proportional to the rate of change in furnace temperature, and, as has been made apparent, on a change in the furnace temprature the thermocouple 412 of Fig. l operates to temporarily increase the corrective adjustment then produced by the thermocouple 4i.

As previously stated, the production of a corrective control effect immediately on a change in a control condition, followed by a delayed control effect opposite in direction to, but smaller in magnitude than the first effect, is conducive to close regulation with little or no hunting tendency, provided the two control effects are suitably proportioned with respect to the controlling condition change giving rise to those effects and to the characteristics of the furnace heating operation or other process in which the control effects are used. The provision of the adjustable contact 43', as shown, facilitates such proportioning of the two control effects.

For optimum results in the use of the invention in the form shown in Fig. l, the values of the resistance 43 and of the condenser 45 should be suitably related to the operating characteristics of the furnace. The furnace characteristics which thus have to be taken into account depend upon such matters as the heat storage capacity of the furnace walls, the heat absorbing capacity of the work, and the furnace and work temperatures. Merely by way of illustration sistance 3Q.

resistance l9. of the photocell 5i exceeds that of the photocell 55, the potential drop across resistance 19 will andexample, I note that in one use of apparatus differing essentially from that shown in Fig. 2 only in that the instrument 33 is used to measure and record furnace temperature conditions without subjecting the furnace to corresponding control actions, the resistance, has a value of 200 ohms and the condenser has a value of 4,000 mid.

The electronic amplifier 58 employed in the arrangement shown in Fig. ,1 may take various forms, one suitable form being illustrated in Fig. 3. As shown in Fig. 3, the photocells 56 and 51 are connected in a bridge circuit, one branch of which includes the cell 56 and a resistance 61,

.while the other branch includes the cell 51 and a resistance 68. The bridge circuit receives energizing current from a section of the secondary'winding 69 of a transformer 10, which has .lts primary winding H connected to and energized by alternating current supply conductors .59 and 69.

The transformer It also includes an additional secondary winding 12, the purpose of which is hereinafter explained.

mon biasing resistance 13 to the terminals of the resistances ii! and til, respectively, remote from the photoelectric cells 56 and 57. Plate energizing current is supplied to the triodes l6 and I! by the transformer secondary winding'69. As shown, the plate circuit of the triode 16 includes a resistance 19 connecting the upper end of the winding 59 to the plate of the triode '16, and a connection including the resistance l3 between the cathode of tricde 2'6 and the lower end of the secondary B5. The plate circuit for the triode ll differs from that for the triode 16 only in'that theplate of triode i? is connected to the upper end of the transformer secondary 69 by a re- A condenser ill of suitable value is connected betwecnthe ends of. the resistances 19 and 853, respectively adjacent the plates of the triodes T5 and 1?.

When the photocells 56 and 5! are equally illuminated, the triodes l6 and T! will be equally of the photocell relative to that of the photocell 57, the triode ll will be rendered more conductive than the triode it and the potential drop across resistance 38 will then exceed that across Conversely, when the illumination an electronic valve 33. The valves 82 and 83 are shown as tetrodes, receiving energizing current from the transformer secondary windings 69 and 72 which are connected in series so that their voltages are additive. As shown, the plate circuit of the tetrode 32 includes one winding BIA of the motor 6! through which the anode of the valve 82 is connected to the lower terminal of the secondary winding 12, and a cathode biasing resistance 84 connecting the cathode of the valve 82 to the upper end of the secondary winding 69. The plate circuit of the tube 83 includes the winding 5IB of the motor 6! through which the anode of valve 83 is connected to the lower end of the secondary winding 12, and includes the resistance 84 through which the cathode of the valve 83 is connected to the upper end of the winding 69. The screen grids of the tetrodes 82 and 83 are connected to the junction between the secondaries 69 and i2. V, A third winding SIC of the motor is also energized. from the transformer secondary windings (i9 and 12 through a condenser 85 of suitable value. The motor windings BIA, 61B and SIC are so related and disposed that reaction between the magnetic fields produced by the windings 6| B and BIC tends to produce rotation of the motor 6| in one direction, while the reaction between the magnetic fields produced by the windings 61A and SIC tends to rotate the motor in the opposite direction. In consequence, the motor 61 rotates in one direction or the other accordingly as the energization of the winding 6 IA exceeds or is less than that of the winding (MB, and the motor stalls when the windings BIA and BIB are similarly energized.

The plate circuits of the tubes 82 and 83 are connected across the transformer secondary windings 69 and 12 in a direction opposite to that in which the plate circuits of the triodes IS and T1 are connected across the transformer secondary winding 59. In consequence, control of the conductivity of, the tubes 82 and $3 in .ac-

cordancewith the potential drops across the resistance '19 and 80 is permitted because the condenser 8! holds over the potential drops produced across the resistances l9 and 80 in one-half cycle when the triodes 16 and T! are conductive, to the next half cycle when the tubes 92 and 83 are conductive Upon an increase in the potential drop across the resistance 19 relative to that across the resistances 80, the tube 83 will be rendered more conductive than the tube 82, and the energizing current in the motor winding SlB will thenexneed that in the motor winding MA, and the motor 6| will rotate in one direction. Conversely, upon an increase in the potential drop across the resistance 80 relative to that across the resistance '19; the tube 82 will become more conductive than the tube 83, the energization of the motor winding 6|A will exceed that of the winding SIB and the motor 6i will rotate in the opposite direction. The apparatus shown in Figs. 1-4 is well adapted for its intended use, but is subject to modification; In somecases, for example, it may be-advantageous to employ in lieu of a single thermocouple ll in each of the chambers i3 and 23, a plurality of such thermocouples collectively providing an average of the temperatures at a plurality of points in each chamber. Similarly, there-may be a plurality of thermocouples 42 in each chamber to collectively respond to the averageof the rates of change of the temperatures at a plurality of points in the chamber. In Fig. 5

'I have illustrated, more or less diagrammatically, a modification, including such a plurality of thermocouples M and 32 in the chamber 83.

As shown in Fig. 5 the thermocouples il may de= sirably be connected in series with each other, and similarly, the thermocouples lZmay also be connected in series with each other.

The modification of Fig. 5 also incorporates provisions for selectively connecting either the thermocouples 42 alone to the instrument 33 or for connecting both the thermocouples 4.! and 42 to said instrument. These. provisions comprise a, single pole-double throw switch 33A which in its dotted line position connects only the thermocouples :32 to the instrument 33, and which in its full line position. connects both the thermocouples 4| and 42 to the instrument 33. When the switch 33A is in its dotted line position, the instrument 33 provides a record of, and operates to effect a control action in response to the rate of change of the temperatures at a plurality of points in the chamber !3 independently of the actual magnitudes of those temperatures. When the apparatus is so employed, the instrument 33 is preferably of the form adapted to assume a center or intermediate position when the applied voltage under measurement is zero. With the switch 33A in its full line position the instrument 33 provides a record of and operates to effect a control action in joint response to the rate of change of temperature at a plurality of points in the chamber I 3 and the average magnitude of the temperature at a plurality of points within the chamber [3. It will be understood that the plurality of points in the chamber l3 to the temperature of which the thermocouples 4| respond, may be the same as, or if desired may be as shown, different from the points to changes in the temperature of which the thermocouples 42 respond. The present application is a division of my prior application Serial No. 440,163, filed April 23, 1942, now Patent No. 2,413,128.

While in accordance with the provisions of the statutes, I have illustrated and described the best forms of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the forms of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A system for controlling the regeneration of catalytic material having carbon deposited thereon comprising a chamber for the catalytic material having a first valved inlet conduit for the introduction of a regeneration gas, a second valved inlet conduit for the introduction of an inert gas, a thermocouple arranged within said chamber to respond to changes in temperature of said catalytic material, a condenser having one terminal connected to one terminal of said thermocouple, a resistor connecting the second terminal of the condenser to the second terminal of the thermocouple, a second thermocouple arranged within said chamber to respond to changes in temperature of said catalytic material and having one terminal connected to said second terminal of the first mentioned thermocouple, means responsive to the voltage difference between the second terminal of the second thermocouple and the second terminal of said condenser, said last named means being constructed and arranged to operate the valves of the first and second conduits.

2. A system for controlling the regeneration of catalytic material having carbon deposited thereon comprising a chamber for the catalytic material having a first valved inlet conduit for the introduction of a regeneration gas, a second valvedv inletconduit for. the introduction of an inert gas, a-thermocouple arranged within said chamber to respond to changes in temperature of said catalytic material, a condenser having one terminal connected to one terminal of said thermocouple, a resistor connecting the second terminal oi the condenser to the second terminal of the thermocouple, means responsive to an ill-- crease of predetermined magnitude in the voltage difference between saidsecond terminals, said last named means being constructed and arranged to operate the valves of the first and sec- 0ndconduits.-

3;, A system for controlling regeneration of catalytic material having carbon deposited thereon, comprising a chamber for the catalytic material having a first inlet conduit for the introduction of hot air and regulatin means adjustable to permit and to prevent flow of hot air into the chamber through said first conduit, a second inlet conduit for the introduction of steam and regulating means adjustable to permit and to prevent the flow of steam into said chamber through said second conduit, a thermocouple arranged within said chamber to respond to changes in the temperature of said catalytic material, a condenser having one terminal connected to one terminal of said thermocouple, a resistor connecting the second terminal of the condenser to the second terminal of the thermocouple, thermometric means arranged within said chamber to respond to changes in said temperature and to create a control force varying with said temperature, and means connected to said second terminals so as to be responsive to the voltage diiference between said second terminals and so constructed and arranged with respect to said thermometric means as to be responsive also to said force, said last mentioned means being constructed and arranged to operate said adjustable means associated with said first and second conduits.

4. A system for controlling regeneration of catalytic material having carbon deposited thereon, comprising a chamber for the catalytic material having a first inlet conduit for the introduction of hot air and regulating means adjustable to permit and to prevent flow of hot air into the chamber through said first conduit, a second inlet conduit for the introduction of steam and regu lating means adjustable to permit and to prevent the flow of steam into said chamber through said second conduit, a thermocouple arranged within said chamber to respond to changes in the temperature of said catalytic material, a condenser having one terminal connected to one terminal of said thermocouple, a resistor connecting the second terminal of the condenser to the second terminal of the thermocouple, thermometric means arranged within said chamber to respond to changes in said temperature and to create a voltage difference varying with the last mentioned temperature, and means connected to said thermometric means and to said second terminals so as to be responsive to the resultant of said voltage difference and the voltage difference between said second terminals, said last mentioned means being constructed and arranged to operate said adjustable means associated with said first and second conduits.

5. A system for controlling regeneration of catalytic material having carbon deposited thereon, comprising a chamber for the catalytic material having a first inlet conduit for the introduction of hot air and regulating means adjustable to' permit and to prevent flow of hot air into the chamber through said first conduit, a second inlet conduit for the introduction of steam and regulating means adjustable to permit and to prevent the flow of steam into said chamber through said second conduit, a thermocouple arranged within said chamber to respond to changes in the temperature of said catalytic material, a condenser having one terminal connected to one terminal of said thermocouple, a resistor connecting the second terminal of the condenser to the second terminal of the thermocouple electrical means arranged within said chamber to respond to changes in said temperature and to create a voltage difference varying with said temperature, and means connected to said electrical means and to said second terminals so as to be responsive to the resultant of said voltage difference and the voltage difierence between said second terminals, said last mentioned means being constructed and arranged to operate said adjustable means associated with said first and second conduits.

WALTER P. WILLS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 5 2,073,650 Prickett Mar. 16, 1937 2,282,726 Jones May 12, 1942 2,316,240 Harrision Apr. 13, 1943 2,330,767 Welty, Jr. Sept. 28, 1943 

1. A SYSTEM FOR CONTROLLING THE REGENERATION OF CATALYTIC MATERIAL HAVING CARBON DEPOSITED THEREON COMPRISING A CHAMBER FOR THE CATALYTIC MATERIAL HAVING A FIRST VALVED INLET CONDUIT FOR THE INTRODUCTION OF A REGENERATION GAS, A SECOND VALVED INLET CONDUIT FOR THE INTRODUCTION OF AN INERT GAS, A THERMOCOUPLE ARRANGED WITHIN SAID CHAMBER TO RESPOND TO CHANGES IN TEMPERATURE OF SAID CATALYTIC MATERIAL, A CONDENSER HAVING ONE TERMINAL CONNECTED TO ONE TERMINAL OF SAID THERMOCOUPLE, A RESISTOR CONNECTING THE SECOND TERMINAL OF THE CONDENSER TO THE SECOND TERMINAL OF THE THERMOCOUPLE, A SECOND THERMOCOUPLE ARRANGED WITHIN SAID CHAMBER TO RESPOND TO CHANGES IN TEMPERATURE OF SAID CATALYTIC MATERIAL AND HAVING ONE TERMINAL CONNECTED TO SAID SECOND TERMINAL OF THE FIRST MENTIONED THERMOCOUPLE, MEANS RESPONSIVE TO THE VOLTAGE DIFFERENCE BETWEEN THE SECOND TERMINAL OF THE SECOND THERMOCOUPLE AND THE SECOND THERMINAL OF SAID CONDENSER, SAID LAST NAMED MEANS BEING CONSTRUCTED AND ARRANGED TO OPERATE THE VALVES OF THE FIRST AND SECOND CONDUITS. 